Chord (geometry)

A chord of a circle is a straight line segment whose endpoints both lie on the circle. A secant line, or just secant, is the infinite line extension of a chord. More generally, a chord is a line segment joining two points on any curve, for instance an ellipse. A chord that passes through a circle's center point is the circle's diameter.

Chords of a circle

Among properties of chords of a circle are the following:

The area that a circular chord "cuts off" is called a circular segment.

Chord is from the Latin chorda meaning bowstring.

Chords of an ellipse

The midpoints of a set of parallel chords of an ellipse are collinear.

Chords in trigonometry

Chords were used extensively in the early development of trigonometry. The first known trigonometric table, compiled by Hipparchus, tabulated the value of the chord function for every 7.5 degrees. In the second century AD, Ptolemy of Alexandria compiled a more extensive table of chords in his book on astronomy, giving the value of the chord for angles ranging from 1/2 degree to 180 degrees by increments of half a degree. The circle was of diameter 120, and the chord lengths are accurate to two base-60 digits after the integer part.

Chord (astronomy)

In the field of astronomy the term chord typically refers to a line crossing an object which is formed during an occultation event. By taking accurate measurements of the start and end times of the event, in conjunction with the known location of the observer and the object's orbit, the length of the chord can be determined giving an indication of the size of the occulting object. By combining observations made from several different locations, multiple chords crossing the occulting object can be determined giving a more accurate shape and size model. This technique of using multiple observers during the same event has been used to derive more sophisticated shape models for asteroids, whose shape can be highly irregular. A notable example of this occurred in 2002 when the asteroid 345 Tercidina underwent a stellar occultation of a very bright star as seen from Europe. During this event a team of at least 105 observers recorded 75 chords across the asteroid's surface allowing for a very accurate size and shape determination.

Chord (concurrency)

A chord is a concurrency construct available in Polyphonic C♯ and Cω inspired by the join pattern of the join-calculus. A chord is a function body that is associated with multiple function headers and cannot execute until all function headers are called.

Synchronicity

Cω defines two types of functions synchronous and asynchronous. A synchronous function acts like a standard function in most Object-Oriented Language, upon invocation the function body is executed and a return value may or may not be returned to the caller. An asynchronous function acts similar to a function that returns void except that it is guaranteed to return immediately with the execution being done in a separate thread.

References

Memory

In psychology, memory is the process in which information is encoded, stored, and retrieved. Encoding allows information from the outside world to be sensed in the form of chemical and physical stimuli. In the first stage the information must be changed so that it may be put into the encoding process. Storage is the second memory stage or process. This entails that information is maintained over short periods of time. Finally the third process is the retrieval of information that has been stored. Such information must be located and returned to the consciousness. Some retrieval attempts may be effortless due to the type of information, and other attempts to remember stored information may be more demanding for various reasons.

From an information processing perspective there are three main stages in the formation and retrieval of memory:

Memory (2008 film)

Memory is a Thai horror film released in 2008. It stars Ananda Everingham and Mai Charoenpura.

Plot

Krit, a married psychiatrist in Chiang Mai, is tasked with looking in on Phrae, an abused, 7-year-old girl. Her mother, Ing-orn, cannot explain the bruises on the girl's body. As he participates in the case, Krit finds himself falling in love with Ing-orn.

References

Memory (2006 film)

Memory (also billed as mem-(o)-re and Memore) is a 2006 American techno-thriller film written by Bennett Joshua Davlin, and starring Billy Zane, Tricia Helfer and Terry Chen.

Plot

While lecturing in Brazil, Dr. Taylor Briggs an American authority on memory consults on a patient found deep in the Amazon. During the exam, Taylor is accidentally exposed to a mysterious substance which unlocks a series of memories in his brain. Memories that are not his. The memory of a killer who committed crimes before Taylor was even born. A killer who is much closer than you may think.

The mystery will rip open Taylor Brigg’s well crafted life, estranging his relationship with his best friend Dr. Deepra Chang, leading him into romance with a beautiful, enigmatic painter Stephanie Jacobs, straining his relationship with his mom’s best friend Carol Hargrave, causing him to question the surrogate father figure in his life, Dr. Max Lichtenstein.

Cast